When an outdoor air temperature is high, required cooling capability in cooling operation of an air conditioner increases, and thus it is required to increase a flow rate of refrigerant which circulates through the air conditioner. On the other hand, when the outdoor air temperature is low, required cooling capability in the cooling operation of the air conditioner decreases, and thus it is required to decrease the flow rate of the refrigerant which circulates through the air conditioner. That is, in the cooling operation of the air conditioner, it is required to appropriately adjust the flow rate of the refrigerant which circulates through the air conditioner in accordance with the outdoor air temperature.
Further, conventionally, air conditioners in which the degree of opening of an expansion valve is adjustable have been proposed. For example, Japanese Patent Laying-Open No. 56-151858 (PTD 1) discloses, as conventional art, a supercooling control device for a refrigerator as an expansion valve whose degree of opening is adjustable. In this supercooling control device for a refrigerator, the temperature of refrigerant at an outlet of a condenser is detected as thermal change by a temperature sensitive cylinder attached to an outlet pipe. This thermal change is converted into pressure change of a heated medium enclosed in the temperature sensitive cylinder. A diaphragm is displaced by this pressure change, and thereby a valve body connected to the diaphragm is displaced. A gap between the valve body and a valve seat is adjusted by the displacement of the valve body. Thereby, a throttle amount of the valve is adjusted.